A complex electronics system for an application, for example a smartphone, laptop computer, etc., may have a variety of interconnected complex chips, each known as a System on a Chip (SOC). Each SOC may include a processor, memory, and external interfaces to perform certain functions. Functions that a SOC may perform include computation, audio processing, video processing, signal processing, sensing, filtering, etc. In addition, each SOC may have a separate power management integrated circuit (PMIC) to supply it with regulated dc power at different voltage levels. Thus, inter-process communication (IPC) and control signaling among the various chips are needed.